Radio frequency (RF) transmission is used in a wide range of communications applications. In many RF communications systems, fixed transmitters and/or receivers are deployed, which may serve large numbers of users and operate at relatively high power levels. In most applications, high availability of the transmission system is essential or, at the very least, is expected by users. Accordingly, for commercial, technical and safety reasons it is desirable to incorporate appropriate monitoring devices within these systems, to enable changes in performance and/or failures of equipment to be identified and rectified quickly and safely.
U.S. Pat. No. 8,983,415, issued on 17 Mar. 2015, discloses a monitoring apparatus that is able to monitor individual frequency channels in an RF signal band. The apparatus comprises an electronic processor which is configurable to operate a tunable filter to select desired channel sub-bands, and to measure characteristics of channels, such as power levels. The measurements are used to provide monitoring signals, including indications and/or alarms if any measured quantities, associated with any one or more channels, fall outside acceptable operating ranges.
The abovementioned apparatus is thus able to monitor individual signals and/or sub-bands, and can be employed to reduce the number of monitoring devices required at sites operating over multiple frequency bands.
It is an object of the present invention to provide for a further reduction in the number of monitoring devices required to be deployed within RF communications systems.